NaCl Casting Technique Really Earns Its Salt

February 28, 2026 by Tyler August 18 Comments

Sodium Chloride has a melting point of 801 C (1,474 F), putting it comfortably between commonly-cast materials like aluminum and bronze. Which led to [Robinson Foundry] asking the question: can you cast salt like a metal? The answer, surprisingly, was yes!

[Robinson] tries casting the salt with two different methods: like it was glass, and like it was metal. In the glass-like casting, he packs a ceramic mold with salt and tosses it into an electric kiln, there to melt and very slowly cool. In metal-like casting, he just tosses salt into a crucible and melts it in the same beer-can kiln we saw when we featured his lost-pla casting a while back. The molten salt is poured very carefully into sand casting molds. If you’re familiar with the technique, you can skip to about 5:20 when he does the reveal.

As it turns out, the sand casting works out much better. While the glass-style casting in the electric kiln grew much larger crystals and so is more translucent, it’s also stuck completely inside the porous ceramic. Perhaps the ceramic would need glazed to pull off that technique?

On the other hand, the sand reacts with the salt in some way– molten salt isn’t exactly a noble gas, after all–to create a lovely gunmetal finish to the parts. They almost look like metal, though the brittleness gives away the game when he opens the mold to show a dagger in several pieces. For the decorative busts and megalodon teeth in the test, though, it is a great success.

Now, we’re not going to say this video came about because of high metal prices, or comment on what sort of trade policies might be driving up the price of metals like aluminum in the USA, but we do think this a great hack. While salt-based castings are obviously going to have very different physical properties than metal, for decorative work, it creates a lovely finish out of a material that’s cheap as dirt. Hopefully he comes back to the glass-style casting; we would not want to trust that black coating around food, and a salt crystal salt shaker sounds too good to pass up.

The only times we’ve seen molten salt around here is in nuclear reactors, and in homemade batteries, though that first one obviously wasn’t table salt.

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Easily Replaceable USB-C Port Spawned By EU Laws

February 26, 2026 by Lewin Day 132 Comments

The USB-C port has become a defacto connectivity standard for modern devices, largely supplanting the ugly mess of barrel jacks and micro USB connectors that once cursed us. While their reliability is good, they don’t last forever, and can be a pain to replace in most devices if they do fail. However, a new part from JAE Electronics could change that.

The problem with replacing USB connectors in most hardware is that they’re soldered in place. To swap them out, you have to master both desoldering and soldering leads of a rather fine pitch. It’s all rather messy. In the interest of satisfying the EU’s new Ecodesign for Sustainable Products Regulation (ESPR), JAE Electronics has developed a USB-C connector that’s easier to replace. Rather than being soldered in, the part is simply clamped down on to a printed circuit board with small screws. As the part is torqued down, small gold-plated contacts are compressed into pads on the PCB to make the necessary contact.

The connector is fully compatible with USB 4 version 2.0. (Don’t ask us how they number these things anymore.) It comes in single and dual connector versions, and is capable of USB PD EPR at up to 240 W (5A/48V). The part does have some drawbacks—namely, the footprint of the metal-shelled part is somewhat larger than most soldered USB C connectors. Whether this precludes its use is very much an application-specific matter for product engineers to decide.

In any case, if you find yourself designing hardware with heavily-used USB C ports, you might find this part useful. It’s not widely available yet, but some parts should be landing at Mouser in coming months. We’ve explored some of the ways USB-C connectors can be fouled and damaged before, too. Sound off with your opinions on this new part in the comments.

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Peltier Fridges Have Early Death

February 24, 2026 by Al Williams 20 Comments

If you know about Peltier modules, a solid-state fridge seems like an easy project. Pump 12V into the module, include a heat sink and a fan. Then you are done, right? According to [Peltier Power], this is not the way to design things, but it is common enough to give these units a reputation for failing quickly.

The problem is that while it makes sense that an inefficient Peltier module needs more power to get more cooling. But the reality is in practical applications, many designs push the current up when it should be moving it down. The curve describes a parabola, and you can be on the high side or low side and still get the same result. But obviously, you don’t want to put in more current and get the same cooling that you could get with lower currents.

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Using 3D Printed Breadboards To Accommodate Wide Boards

February 17, 2026 by Maya Posch 36 Comments

Although off-the-shelf breadboards are plentiful and cheap, they almost always seem to use the same basic design. Although you can clumsily reassemble most of them by removing the voltage rail section and merging a few boards together, wouldn’t it be nice if you had a breadboard that you could stick e.g. one of those wide ESP32 development boards onto and still have plenty of holes to poke wires and component leads into? Cue [Ludwin]’s 3D printable breadboard design that adds a big hole where otherwise wasted contact holes would be.

The related Instructables article provides a visual overview of the rationale and the assembly process. Obviously only the plastic shell of the breadboard is printed, after which the standard metal contacts are inserted. These contacts can be ‘borrowed’ from commercial boards, or you can buy the contacts separately.

For the design files there is a GitHub repository, with breadboard designs that target the ESP32, Raspberry Pi Pico, and the Arduino Nano. An overview of the currently available board designs is found on the Hackaday.io project page, with the top image showing many of them. In addition to the single big space design there are also a few variations that seek to accommodate just about any component and usage, making it rather versatile.

Real-Time 3D Room Mapping With ESP32, VL53L5CX Sensor And IMU

February 14, 2026 by Maya Posch 14 Comments

ST’s VL53L5CX is a very small 8×8 grid ranging sensor that can perform distance measurements at a distance of up to 4 meters. [Henrique Ferrolho] demonstrated that this little sensor can also be used to perform a 3D scan of a room. The sensor data can be combined with an IMU to add orientation information to the scan data. These data streams are then combined by an ESP32 MCU that streams the data as JSON to a connected computer.

Of course, that’s just the heavily abbreviated version, with the video covering the many implementation details that crop up when implementing the system, including noise filtering, orientation tracking using the IMU and a variety of plane fitting algorithms to consider.

Note that ST produces a range of these Time-of-Flight sensors that are more basic, such as the VL53VL0X, which is a simple distance meter limited to 2 meters. The VL53L5CX features the multizone array, 4-meter distance range, and 60 Hz sampling speed features that make it significantly more useful for this 3D scanning purpose.

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Building The Most Simple Motor In Mostly LEGO

February 14, 2026 by Maya Posch 13 Comments

Although [Jamie’s Brick Jams] has made many far more complicated motor design in the past, it’s nice to go back to the basics and make a motor that uses as few parts as possible. This particular design starts off with a driver coil and a magnetic rotor that uses two neodymium magnets. By balancing these magnets on both sides of an axis just right it should spin smoothly.

The circuit for the simple motor. (Credit: Jamie's Brick Jams, YouTube) — The circuit for the simple motor. (Credit: Jamie’s Brick Jams, YouTube)

First this driver coil is energized with a 9 V battery to confirm that it does in fact spin when briefly applying power, though this means that you need to constantly apply pulses of power to make it keep spinning. To this end a second coil is added, which senses when a magnet passes by.

This sense coil is connected to a small circuit containing a TIP31C NPN power transistor and a LED. While the transistor is probably overkill here, it’ll definitely work. The circuit is shown in the image, with the transistor pins from left to right being Base-Collector-Emitter. This means that the sensor coil being triggered by a passing magnet turns the transistor on for a brief moment, which sends a surge of power through the driver coil, thus pushing the rotor in a typical kicker configuration.

Obviously, the polarity matters here, so switching the leads of one of the coils may be needed if it doesn’t want to spin. The LED is technically optional as well, but it provides an indicator of activity. From this basic design a larger LEGO motor is also built that contains many more magnets in a disc along with two circular coils, but even the first version turns out to be more than powerful enough to drive a little car around.

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Converting AC Irrigation Valves To DC Operation

February 9, 2026 by Lewin Day 33 Comments

Due to historical engineering decisions made many decades ago, a great many irrigation systems rely on solenoid valves that operate on 24 volts AC. This can be inconvenient if you’re trying to integrate those valves with a modern smart home control system. [Johan] had read that there were ways to convert these valves to more convenient DC operation, and dived into the task himself.

As [Johan] found, simply wiring these valves up to DC voltage doesn’t go well. You tend to have to lower the voltage to avoid overheating, since the inductance effect used to limit the AC current doesn’t work at DC. However, even at as low as 12 volts, you might still overheat the solenoids, or you might not have enough current to activate the solenoid properly.

The workaround involves wiring up a current limiting resistor with a large capacitor in parallel. When firing 12 volts down the line to a solenoid valve, the resistor acts as a current limiter, while the parallel cap is initially a short circuit. This allows a high current initially, that slowly tails off to the limited value as the capacitor reaches full charge. This ensures the solenoid valve switches hard as required, but keeps the current level lower over the long term to avoid overheating. According to [Johan], this allows running 24V AC solenoid valves with a 12V DC supply and some simple off-the-shelf relay boards.

We’ve seen similar work before, which was applied to great effect. Sometimes doing a little hack work on your own can net you great hardware to work with. If you’ve found your own way to irrigate your garden as cheaply and effectively as possible, don’t hesitate to notify the tipsline!